In recent years, research and development has been actively done on use of data, which is collected from various sensors in a system as typified by a machine-to-machine (M2M) system, for various applications. In an M2M system, data obtained from various sensors is collected in a time-series manner, and the collected data is transmitted to a management server via a network, in particular, via a mobile network. The management server manages the data collected from various sensors (time-series data) so that various applications can use the data. Currently, such time-series data uniformly consumes resources (for example, the network band and the resources of the management server).
However, such data has different importance, depending on the application or the situation in which the data is used. For example, there is an application that acquires the tracks of moving vehicles by regularly acquiring information about the positions of the vehicles. This application can analyze the traffic congestion status or the like at a certain location. For example, when a vehicle drives on an expressway at a constant speed, many points can accurately be interpolated from rough data points. Namely, data other than representative points (data points) has a low value (not important). In addition, since vehicles drive at a very low speed in an area where a traffic congestion is caused, measurement of data at short intervals is not necessary. However, when a vehicle drives on complicated streets or repeatedly stops and goes, it is difficult to accurately detect the position of the vehicle without many data near each change point. Therefore, even when the same type of data is used (for example, vehicle position information), the data could have different importance, depending on the application or the situation in which the data is used. Namely, the importance of the data changes dynamically.
Patent Literature (PTL) 1 discloses a technique in which vehicle data collected by an on-vehicle portable terminal equipment is classified according to type. In PTL 1, the transmission timing is adjusted on the basis of a predetermined priority. For example, while data relating to safety of a vehicle is transmitted promptly to a management server, non-urgent data such as fault diagnosis information is transmitted after the vehicle is stopped. PTL 2 discloses a technique in which two queues are prepared, each being provided with a priority in advance, and the transmission timing is adjusted. In addition, PTL 3 discloses a configuration in which sensor data is stored in a buffer on the basis of a type of the data, a predetermined calculation is performed, and whether to transmit the data is determined. In addition, PTL 4 discloses a technique in which, on the basis of a fluctuation range of detection data, the importance of data acquired from a sensor is determined and the data transmission frequency is changed.    PTL 1: Japanese Patent Kokai Publication No. JP2011-076322A    PTL 2: Japanese Patent Kokai Publication No. JP2010-026815A    PTL 3: Japanese Patent Kokai Publication No. JP2011-244406A    PTL 4: Japanese Patent Kokai Publication No. JP2011-188338A